What to Expect at Your Anatomy Scan 

Pregnancy is a time of joy and anticipation — it’s normal to be both excited and nervous about your 20-week ultrasound appointment. Read on to learn more about this scan and what to expect.

About Anatomy Scans

This ultrasound, sometimes called the fetal survey, is done between 18 and 22 weeks of pregnancy. The best time is usually between 20 to 21 weeks. It’s one of the most detailed ultrasounds you’ll have and a chance to see your growing baby. At around 20 weeks, your baby’s size allows for a clear look at their development and growth.

Your sonographer will capture images you can take home as a keepsake. If you’d like to know your baby’s sex — or prefer to keep it a surprise — just let them know before the ultrasound begins.

How to Prepare

It's normal to be excited and sometimes nervous about the ultrasound. Here are some tips to help it go smoothly:

• Drink water before your appointment. You may be asked to drink about two glasses of water around 45 minutes before your scan. A full bladder helps move your uterus so it’s easier to get clear images. If you’re not sure, call your ultrasound office and ask if they recommend drinking water before your appointment.
• Bring a supportive person. Choose someone who helps you feel calm, not necessarily the person who is the life of the party. While it’s exciting to see your baby, this is a medical exam and there is a lot of sitting and waiting while the exam is done. The scan usually takes 30–60 minutes (sometimes longer).
• Know what to expect. This is a medical test, so video recording isn’t allowed. But don’t worry — you’ll get pictures to take home at the end of your visit.

What to Expect During the Scan 

During the scan, the sonographer will apply gel to your belly and move a small device called a transducer across your skin. The transducer uses safe sound waves to create images of your baby on a monitor. The sonographer will take pictures and measurements of many parts of your baby, including:

• Arms, legs, hands, fingers, feet and toes
• Brain, head, neck and spine
• Chest and lungs
• Heart
• Kidneys and bladder
• Lips, chin, nose, eyes and face
• Stomach and intestines

They will also:

• Assess the placenta’s position
• Check blood flow in the umbilical cord and its connection to the placenta
• Examine your uterus, ovaries and cervix
• Measure the amount of amniotic fluid
• Record your baby’s heart rate

During the scan, your sonographer may get very quiet while they take pictures. This doesn’t mean anything is wrong — they just need to focus. Try to be patient.

It can be tempting to ask them to explain everything they see, but their main job is to take clear images for the doctor to review. The sonographer will share any information the physician has authorized them to.  

Your center will let you know when you can expect the ultrasound results. Every office is a little different in how they share them.

Sometimes, your baby’s position may make it difficult to see everything clearly. If this happens, your sonographer may need to use a transvaginal probe to get measurements. Sometimes they’ll ask you to move around and help you get into a different position, or your care team may ask you to come back later in hopes that your baby has moved into a better position.

What Ultrasound Scans Detect

This ultrasound looks at many parts of your baby to see how they’re growing, including the brain, spine, heart, limbs and abdominal organs. If something doesn’t appear to be developing as expected, your provider may suggest a follow-up scan or additional tests to better understand what’s happening and work with you on a care plan.

Keep in mind that no ultrasound can detect everything. Factors like your baby’s position, amniotic fluid levels, body type or scar tissue can sometimes make it harder to see certain details, so a second look may be needed even if everything is normal.  

The results help you and your care team prepare and make informed decisions about your pregnancy and your baby’s care after birth. Remember, the 20-week ultrasound is a screening, not a diagnosis. If your care team sees anything that needs a closer look, they’ll order additional tests.

If you have any questions or concerns, don’t hesitate to reach out to your care team. They’re here to support you and ease your worries.